This is a good place to start:

> We have all become like one who is unclean, and all our righteous
deeds are like a polluted garment. We all fade like a leaf, and our iniquities, like the wind, take us away. -- [Isaiah 64:6, ESV](http://www.biblegateway.com/passage/?search=Isaiah%2064:6&version=ESV)

Btw, the Hebrew for "polluted garment" is more literally "menstrual rag".

But I think there is a lot of misunderstanding about total depravity. The Heidelberg Catechism [has this to say][1] about what it means to do something good:

> Q91. What do we do that is good? 

> A. Only that which
>       arises out of true faith,
>       conforms to God's law,
>       and is done for his glory;    and not that which is based
>       on what we think is right
>       or on established human tradition.

And who would argue that natural man can do anything that fits that definition apart from grace? Here is the [Canon of Dordt][2] on the topic of total depravity:

> Therefore all men are conceived in sin, and by nature children of
> wrath, incapable of saving good, prone to evil, dead in sin, and in
> bondage thereto, and without the regenerating grace of the Holy
> Spirit, they are neither able nor willing to return to God, to reform
> the depravity of their nature, nor to dispose themselves to
> reformation.

If you simply delete the word "regenerating" from that article, you get something that both John Wesley and [Thomas Aquinas][3] could agree to (because of prevenient grace).

Understood this way, total depravity is not a "Calvinist" doctrine but one affirmed by the whole western church (the Eastern Orthodox have a distinctly different understanding of original sin). It only becomes Calvinist-specific when you start arguing over prevenient vs. regenerating grace, which to me seems like a pretty minor issue.


  [1]: http://www.crcna.org/pages/heidelberg_gratitude.cfm
  [2]: http://www.prca.org/cd_text3.html
  [3]: http://www.ccel.org/ccel/aquinas/nature_grace.viii.i.ii.html